Sooner or later, one of these projects will counter-sue for misuse of copyright.
Misuse of copyright is when a copyright holder attempts to illegitimately expand the rights granted to them by their copyright in some work (in this case, quashing competition from distribution channels that are used to distribute unrelated copyrighted material).
The normal punishment for misuse of copyright is the rendering of the copyright unenforceable. The letter clearly sets the scope of the copyrights that would be at stake in this case:
" each of the major motion picture studios in the United States, specifically, Paramount Pictures Corporation, Sony Pictures Entertainment Inc., Universal City Studios LLC, Warner Bros. Entertainment Inc., Walt Disney Studios Motion Pictures, Netflix Studios, LLC, and their respective affiliates (collectively, the “MPA Member Studios”), which own or control exclusive rights under copyright in and to a vast number of motion pictures and television shows."
I'm not a lawyer, but misuse of copyright / trademark should be covered in any decent introduction to intellectual property law course. The MPA lawyers are either incompetent or working under the assumption that their clients are invincible / above the law.
I think pushing back on this take down notice would be a slam dunk case.